Fuse.



Patented Dec. 23, |902'.

NIL 7|6,398.

. L. R. EMMET.

v Fuss.

(Application led Aug. 24, 1898.)

(lo Modal.)

YH: Noam versus ca. moraumo. wasmnmon. n. cA

' UNITED STATES PATENT OEEICE.

YILLIAM L. R. EMMET, OF SOHENECTADY, NEW YORK, ASSIGNOR TO THE I GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

FUSE.

SPECIFICATION forming part of Letters Patent No. 716,398, dated December23, 1902.

Application iiled August 24,1898. Serial No. 689,378. (No model.)

To all whom t may concern:

Be it known that I, WILLIAM LE ROY EM- MET, a citizen of the UnitedStates, residing at Schenectady, county of Schenectady, State of NewYork, have invented certain new and useful Improvements in Fuses, ofwhich the following is a specification.

The present invention relates to apparatus for extinguishing the arcformed by the blowing of a safety-fuse. The object of the invention isto provide a fusible cut-out in which the arc formed by the melting ofthe fuse willbe quickly and with certainty broken and blown out.

The nature of my invention will be more clearly apprehended by referenceto the following description, taken in connection withv the accompanyingdrawings. The scope of the invention will be particularly pointed out inthe appended claims.

Figure 1 is an end elevation, partly in section, of a cut-out made inaccordance with my invention. Fig. 2 is a side View of the same, partlyin section.

The cut-out proper is composed of a baseplate1,ofinsulatingmaterial,having attached thereto side plates 2 2, which serveas guards. Mounted on the base-plate at suitable distances apart are twocastings having ears 3 3. Pivoted to each pair of ears is a bifurcatedor U -shaped spring-actuated arm 4. The actuating-spring 5 is coiledabout the pivot 6 between the bifurcations of the arm 4. One end of thespring engages the arm and the other end the body of thesupporting-casting '7. The springs are so arranged as to urge the upperends of the arms away from each other. Suitable clamping devices 8 arearranged at the outer extremity of the arms, between which a fuse 9 issecured, so as to hold the arms in a position perpendicular to the base7, as shown. The fuse is thus normally maintained in a state of tension.Permanently mounted between the arms and overlapping an end of each ofthe castings 7 is a block of insulating material 10. Superposed thereonare two renewable blocks 11 and 12, of insulating material, each blockhaving a hollow formed therein, so that when placed together as shown inthe drawings a chamber 13 is formed. An opening 14: in the upper block11 communicates with the chamber so formed. y

The arms and insulating-blocks are so proportioned and arranged as toallow the fuse 9 to pass freely between the Iblocks 11 and 12 andthrough the chamber 13. That portion of the fuse passing through thischamber is made of smaller cross-section than the remaining parts inorder to insure the forma- 6o tion of the arc within the' chamberinstead of between the insulating-blocks.

In order to prevent any possibility of the arc formed in the chamber 18from passing to either of the spring-actuated arms, I nd it advisable toprovide barriers, which in this case are plates 22, of fiber or otherinsulating material, sliding in grooves in the side plates 2. Thebarriers, together with the insulating-blocks, are all held in place bybolts pro- 7o vided with thumb-screws 15. By removing the th umb-screwsand pressing back the bolts the barriers may be slid out of the grooves,and so withdrawn in order to permit the insertion or renewal of thefuse.

In order to make connections with the fuse,

I provide the castings 7 with ns 16, which extend through the base-plateand are adapted to engage springclips 17, carried by theconnecting-bolts 18. The connecting-bolts 8o are passed through abushing 19, which is fitted in an opening in the switchboard 20.Insulators 21 iit over the reduced ends of each of the bushings. Theinsulators and bushings are held rmlyin place by the clamping-nuts onthe connecting-bolts. ,Y

When the fuse blows, the air within the central recess or chamber isVery suddenly heated, and the resulting pressure causes the vaporizedmetal and other gases to be vio- 9o lently expelled through the openingin the chamber, thus blowing out the arc. As soon as the fuse parts thespring-arms come into action and instantly withdraw the ends of the fusefrom the chamber and from contact with the insulating-blocks. By thesimultaneous expulsion of the gases from the chamber and the withdrawalof the fuse ends the continuance of the arc formed by rupture of thefuse is rendered practically impossible.

Afurther incident of the separation of the terminals formed when thefuse melts and IOO between which the arc is sprung is a much more rapidstretching of the arc within the confined space between the two blocks,thereby eecting a rapid augmentation of the resist- 5 ance of the arcstream by reason of the smallness of cross-section of the space betweenthe blocks', which quickly results in an extin- Vguishment of the arc.Both effects take place simultaneously, the expulsion effect due to Iothe pressure through the vent and the increase of resistance due to thestretching of the are, the net result being a very effective action. Y Y

No claim is herein made to the method of I5 extinguishing an arcdescribed in the present application, said matter being claimed in acompanion application, which is asdivision hereof.

What I claim, and desire to secure by Letzo ters Patent of the UnitedStates, is*

l. A fusible cut-out comprising a fusible Yconductor extending throughan opening in insulating-walls, substantially the same size Vas theconductor and of sufficient length to z5 lrupture the arc before thesame is stretched to the ends of the opening, and means for stretchingthe arc to its rupturing-point within said opening and While whollyinclosed thereby when the fuse melts. l

2. A fuse-block having*V a contracted passage for the fuse, aspring-retracted terminal outside of said passage, and a vent of lessresistance to the expulsion of arc gases than the fuse-passage andlocated between the fuseterminals.

3. A fuse-block having a contracted passage for the fuse, a chambercommunicating with said passage, a spring-retracted terminal outside ofthe passage, and a vent in the chamber.

4. In a fusible cut-out, the combination of a fuse having a spot ofreduced conductivity, means for maintaining the fuse under springtension, and an inclosure around the fuse having an opening to theoutside air opposite the reduced fuse-spot. E

In testimony whereof I have hereunto set my hand. 'i

WILLIAM YL. R. EMMET. `Witnessesz SAM P. WIGG,

W. H. OUTCHIN.

